Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Inspection Procedure
Hand-held tester:
- CHECK OPERATION OF STOP LIGHT
- Check if the stop lights go on and off normally when the brake pedal is depressed and released.
- NG: REPAIR OR REPLACE STOP LIGHT SWITCH ASSY
- OK
- INSPECT STOP LIGHT SWITCH ASSY
- Check the resistance between the terminals when the switch is turned ON and OFF.
Standard:
- NG: REPLACE STOP LIGHT SWITCH ASSY
- OK
- Check the resistance between the terminals when the switch is turned ON and OFF.
- READ VALUE OF HAND-HELD TESTER (STP SIGNAL)
- Turn the ignition switch ON.
- Select the item "DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/STOP LIGHT SW" and read its value displayed on the hand-held tester.
Standard:
- OK: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
- NG
- CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)
- Disconnect the S9 stop light switch connector.
- Disconnect the E5 ECM connector.
- Check the resistance between the wire harness side connectors.
Standard (Check for open):
Standard (Check for short):
- Reconnect the ECM connector.
- Reconnect the stop light switch connector.
- NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
- OK
REPLACE ECM (See REPLACEMENT )
OBD II scan tool (excluding hand-held tester):
- CHECK OPERATION OF STOP LIGHT
- Check if the stop lights go on and off normally when the brake pedal is depressed and released.
- NG: REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT
- OK
- INSPECT STOP LIGHT SWITCH ASSY
- Check the resistance between terminals when the switch ON and OFF.
Standard:
- NG: REPLACE STOP LIGHT SWITCH ASSY
- OK
- Check the resistance between terminals when the switch ON and OFF.
- INSPECT ECM (STP VOLTAGE)
- Turn the ignition switch ON.
- Measure the voltage between the terminals of the E4 and E5 ECM connectors.
Standard:
- OK: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
- NG
- CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)
- Disconnect the S9 stop light switch connector.
- Disconnect the E5 ECM connector.
- Check the resistance between the wire harness side connectors.
Standard (Check for open):
Standard (Check for short):
- Reconnect the ECM connector.
- Reconnect the stop light switch connector.
- NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
- OK
REPLACE ECM (See REPLACEMENT )
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
